Genetically engineered enteropathogenic Escherichia coli strain elicits a specific immune response and protects against a virulent challenge

• Published in: Microbes and infection Vol. 5; no. 10; pp. 857 - 867
• Main Authors: Boullier, Séverine, Nougayrède, Jean-Philippe, Marchès, Olivier, Tasca, Christian, Boury, Michèle, Oswald, Eric, De Rycke, Jean, Milon, Alain
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier SAS 01.08.2003; Amsterdam Elsevier; Paris
• Subjects: Adhesins, Escherichia coli - immunology; Administration, Oral; Animals; Anti-AF/R2 Abs; Antibodies, Bacterial - blood; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Bacterial Adhesion - immunology; Bacterial Outer Membrane Proteins - genetics; Bacteriology; Biological and medical sciences; Body Weight; Diarrhea - immunology; Diarrhea - microbiology; Enzyme-Linked Immunosorbent Assay; EPEC O103; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - immunology; Escherichia coli - pathogenicity; Escherichia coli Infections - immunology; Escherichia coli Infections - microbiology; Escherichia coli Proteins - genetics; Fundamental and applied biological sciences. Psychology; Gene Deletion; HeLa Cells; Humans; Intestines - microbiology; Life Sciences; Microbiology; Mutagenesis, Insertional; Rabbit ( Oryctolagus cuniculus); Rabbits; Receptors, Cell Surface - genetics; Vaccine; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; Virulence - genetics; Vaccine; Rabbit ( Oryctolagus cuniculus); EPEC O103; Anti-AF/R2 Abs; Immunoprotection; Animal model; Immune response; Escherichia coli; Rabbit (Oryctolagus cuniculus); Lagomorpha; Vertebrata; Oryctolagus cuniculus; Mammalia; Immunogenicity; Bacteria; Mutation; Attenuated strain; Enterobacteriaceae
• ISSN: 1286-4579; 1769-714X
• DOI: 10.1016/S1286-4579(03)00175-8

Enteropathogenic Escherichia coli (EPEC), a major cause of severe disease with diarrhea in infants, is also involved in weaned rabbit colibacillosis. EPEC O103 is frequent in rabbit-fattening units of Western Europe. It causes high mortality and growth retardation, leading to substantial economic losses. We report here the construction by allelic exchange of an EPEC O103 strain mutated in espB and tir, two essential virulence genes. Upon live oral administration to weaned rabbits, the E22ΔTir/EspB mutant strain efficiently colonized the intestinal tract without any adverse consequences. The rabbits were challenged with the highly pathogenic parental strain E22. The mutant provided complete protection to rabbits and total resistance to intestinal colonization by E22. In addition, E22ΔTir/EspB strain induced a specific humoral response against the bacterial adhesin AF/R2. These Abs prevent bacterial attachment to epithelial cells in vitro. These results open the way for the development of an efficient vaccine strategy against rabbit EPEC infections.